基于ST-6-2核酸适配体的显色探针用于快速检测新冠病毒S蛋白OA

A colorimetric biosensor based on ST-6-2 aptamer and gold nanoparticles(AuNPs)was developed for the rapid detection of the SARS-CoV-2 spike protein.AuNPs with uniform particle size were synthesized using the sodium-citrate reduction method,and the binding conformational change between the aptamer and the spike protein was verified via circular dichroism spectroscopy.Three conjugation strategies for the DNA functionalization of AuNPs,namely the freeze-thaw,salt-aging,and low-pH methods,were compared.The conjugation efficiency was evaluated based on UV-Vis absorption spectra,and the low-pH method was identified as the optimal strategy.A colorimetric probe(AuNPs@SH-DNA)was constructed by covalently coupling thiol-modified cDNA and Poly T to the surface of AuNPs.Based on the principle of competitive lateral-flow chromatography,a test strip was assembled for the visual detection of the spike protein.Experimental results showed that the sensor exhibited favorable signal response toward the spike protein,thus enabling rapid,low-cost,and point-of-care detection.This colorimetric aptasensor platform provides a novel solution for the point-of-care testing of SARS-CoV-2 and demonstrates significant potential for epidemic screening and decentralized diagnostics.